A hoist, such as an electric chain hoist and an electric hoist, includes an electric motor driven by an inverter controller as a motor for lifting and lowering a load. In such a hoist, the inverter controller and other various heat sources (a motor, a regenerative resistor and the like) are accommodated in a casing, and heat generated during an operation has been problematic. For example, heat generated by the inverter controller increases, particularly at the time of a high-load operation. The heat affects a constituent element such as a power transistor of the inverter controller or the like, possibly hindering a normal operation.
The applicant of the present application has proposed a hoist that can efficiently dissipate heat as described above (see JP-A-2008-230751).
The hoist described in JP-A-2008-230751 includes a motor for lifting and lowering a load, a reduction gear mechanism, and a regenerative braking resistance unit, in which the motor is driven by an inverter controller incorporated in a main body of the hoist, and the regenerative braking resistance unit provides a braking effect by supplying a current generated by the motor at the time of lowering a suspended load to the regenerative braking resistance unit. The inverter controller of the hoist is closely attached to a casing of the reduction gear mechanism with surface contact, so that heat generated by the inverter controller is released to the casing of the reduction gear mechanism.